1. Technical Field of the Disclosure
The present disclosure relates to an electromagnetic switch that is operated by an electromagnetic power, and is suitable for a starter of vehicles, for example.
2. Description of Related Art
An electromagnetic switch that has a coil that generates an electromagnetic power by a current flow and a movable core driven by the electromagnetic power generated in the coil is known up to now.
It is known that the electromagnetic switch that has a coil as a magneto motive force source influences an energizing interrupting means that energizes and interrupts energization of the coil by an effect of an inductance of the coil.
Especially, when a point of contact type relay that has a fixed point of contact and a moving point of contact as an energizing interruption means is used, an arc is caused between the fixed point of contact and the moving point of contact when energizing is interrupted that causes abrasion to both fixed point of contact and the moving point of contact.
Especially, in a case for an electromagnetic switch etc. equipped in a starter used for starting an engine of a vehicle that has a function to stop the engine for improving the fuel consumption of the vehicle when stopping at an intersection (so-called idle stop function), a frequency of starting the engine is much higher compared with the past, thus a frequency of operating the electromagnetic switch will also increase.
Therefore, a durability of the energizing interruption means becomes a problem in the above-mentioned electromagnetic switch that uses the coil for the magneto motive force source.
In Japanese Utility Model Application Laid-Open Publication No. 60-102469, for such a problem mentioned above, the current that flows to the energizing interruption means when energizing is interrupted is reduced by connecting the diode electrically in parallel to the coil of the electromagnetic switch so that the anode terminal side of the diode becomes lower potential compared with the cathode terminal side, and returns the current that flows from the inductance of the coil when the energizing is interrupted in the circuit of the coil and the diode.
By the way, it is necessary to install the electromagnetic switch so as not to damage the diode by the vibration when the electromagnetic switch that has the diode disclosed in the above-mentioned publication is exposed to vibration.
Especially, the starter used for starting the engine in the vehicle requires extra care because the electromagnetic switch is exposed to the strong vibration since the starter is usually installed directly to the engine.
Moreover, with the miniaturizing of the product in recent years, the electromagnetic switch used for the product is also requested to be miniaturized.